Ball type continuously variable transmission

ABSTRACT

A variable transmission includes an input shaft, a planetary gear set drivingly engaged with a variator comprising, a variator carrier assembly, a first ring assembly, and a second ring assembly; and the output shaft, arranged to produce transmissions with continuously variable or infinitely variable output ratios.

CROSS-REFERENCES TO RELATED APPLICATIONS

The present application claims the benefit of U.S. Provisional PatentApplication No. 61/786,299, filed Mar. 14, 2013 which application isincorporated herein by reference.

BACKGROUND OF THE INVENTION

Automatic and manual transmissions are commonly used on automobilevehicles. Those transmissions are becoming more and more complicatedsince the engine speed has to be more precisely controlled to limit thefuel consumption and the emissions of cars. This finer control of theengine speed in usual transmissions can only be done by adding morediscrete step ratio gears and increasing the overall complexity andcost. Consequently, 6-speed manual transmissions then become morefrequently used as are 8 or 9 speed automatic transmissions.

SUMMARY OF THE INVENTION

Provided herein is a variable transmission comprising: an input shaft; avariator (CVP) comprising a first ring assembly coupled to the inputshaft, a carrier assembly comprising a plurality of tiltable variatorballs drivingly engaged with the first ring assembly, and a second ringassembly drivingly engaged with the tiltable variator balls; and aplanetary gearset comprising a planet carrier drivingly engaged with theinput shaft, a ring drivingly engaged with the second ring assembly ofthe variator, and a sun gear drivingly engaged with the output of thevehicle; wherein the planetary gearset is configured to split power ofthe input shaft between the variator and a mechanical path goingdirectly to the output through the planetary gear set.

In some embodiments, the first ring assembly and the second ringassembly are drivingly coupled over a continuous range of speed ratiosfrom a minimum speed ratio to a maximum speed ratio, and wherein thespeed ratio is controlled by tiltable variator balls. In someembodiments, the variator controls the speed ratio between the two ringassembly of the variator, and thus between the planet carrier and ringof the planetary gearset. In some embodiments, a minimum speed ratio anda maximum speed ratio between the ICE and sun of the planetary gearset(output) span a range from negative to positive.

In some embodiments, the variable transmission comprises a dampener (ordamper) coupled to the input shaft and disposed between a power sourceand the variable transmission.

In some embodiments, the variable transmission comprises a clutch in thedriveline. In some embodiments, the variable transmission might comprisea clutch coupled to the dampener or at any other location to allowinterrupting power transmission through the driveline.

In some embodiments, the variable transmission comprises an additionalspeed ratio configured to shift a range of speed ratios to high or lowervalues. In some embodiments, the speed ratio shifter comprises acountershaft and gear drivingly engaged with the first ring assembly,the countershaft and gear having a gear ratio that changes the speedratio between the input shaft and the second ring assembly. In someembodiments, the speed ratio shifter is made of a planetary of which oneelement is grounded. In some embodiments, shifting the range of speedratios to higher ratios shifts the range of speed ratios between theplanet carrier and sun of the planetary gearset to lower ratios. In someembodiments, the range of speed ratios is such that the range of speedratios between the ICE and the sun or output spans a negative ratio to apositive ratio. In some embodiments, the range of speed ratios is suchthat the range of speed ratios between the input shaft and the sun oroutput spans a negative ratio to a positive ratio, the negative ratiohaving equal magnitude as the positive ratio.

In some embodiments, the variable transmission comprises an additionalspeed ratio configured to shift a range of speed ratios to high or lowervalues. In some embodiments, the speed ratio shifter comprises aplanetary gear set of which one of the elements (for example the ring)has been grounded to create a speed ratio between the two other elements(for example sun and planet carrier). The two elements not grounded areconnected to the input shaft and the first ring assembly. In someembodiments, shifting the range of speed ratios to higher ratios shiftsthe range of speed ratios between the planet carrier and sun of theplanetary gearset to lower ratios. In some embodiments, the range ofspeed ratios is such that the range of speed ratios between the ICE andthe sun or output spans a negative ratio to a positive ratio. In someembodiments, the range of speed ratios is such that the range of speedratios between the ICE and the sun or output spans a negative ratio to apositive ratio, the negative ratio having equal magnitude as thepositive ratio.

In some embodiments, the variator is an asymmetric variator. In someembodiments, the asymmetric variator performs the function of the speedratio shifter. In some embodiments, the first ring assembly comprises afirst ring assembly engagement portion that is drivingly engaged withthe variator balls, and second ring assembly comprises a second ringassembly engagement portion that is drivingly engaged with the variatorballs, and wherein the first ring assembly engagement portion is offsetfrom the second ring assembly engagement portion such that the speedratio is greater than 1 or less than 1 when the variator balls are nottilted.

In some embodiments, the variator comprises a traction fluid.

Provided herein is a vehicle driveline comprising: a power source, avariable transmission of any configuration described herein or thatwould be obvious to one of skill in the art having read the disclosureherein. The variable transmission of the vehicle driveline is optionallydrivingly engaged with the power source, and a vehicle output drivinglyengaged with the variable transmission.

In some embodiments, the power source is drivingly engaged with thevehicle output. In some embodiments, the vehicle driveline comprises atorsional dampener. In some embodiments, the vehicle driveline comprisesa clutch. In some embodiments, the vehicle driveline comprises avariable transmission of any configuration described herein or thatwould be obvious to one of skill in the art having read the disclosureherein.

Provided herein is a method comprising providing a variable transmissionof any configuration described herein or that would be obvious to one ofskill in the art having read the disclosure herein.

Provided herein is a method comprising providing a vehicle drivelinecomprising a variable transmission of any configuration described hereinor that would be obvious to one of skill in the art having read thedisclosure herein.

Provided herein is a method comprising providing a vehicle comprising avariable transmission of any configuration described herein or thatwould be obvious to one of skill in the art having read the disclosureherein. Provided herein are variable transmissions comprising: an inputshaft; a variator (CVP) comprising a first ring assembly coupled to theinput shaft, a carrier assembly comprising a plurality of tiltablevariator balls drivingly engaged with the first ring assembly, and asecond ring assembly drivingly engaged with the tiltable variator balls;and a planetary gearset comprising a planet carrier drivingly engagedwith the input shaft, a ring drivingly engaged with the second ringassembly of the variator, and a sun gear drivingly engaged with theoutput of the vehicle, wherein the planetary gearset is configured tosplit power of the input shaft between the variator and a mechanicalpath going directly to the output through the planetary gear set. Insome embodiments, the first ring assembly and the second ring assemblyare drivingly coupled over a continuous range of speed ratios from aminimum speed ratio to a maximum speed ratio, and wherein the speedratio is controlled by the tiltable variator balls. In some embodiments,the tiltable variator balls controls the speed ratio between the firstring assembly and second ring assembly of the variator, and therebycontrols the speed ratio between the planet carrier and ring of theplanetary gearset. In some embodiments, a minimum speed ratio and amaximum speed ratio between the input shaft and the sun of the planetarygearset span a range from negative to positive. In some embodiments, thevariable transmission further comprises a damper coupled to the inputshaft and disposed between a power source and the variable transmission.In some embodiments, the variable transmission further comprises aclutch disposed between the power source and the variable transmission.In some embodiments, the clutch is coupled to the damper or at alocation to allow interrupting power transmission. In some embodiments,the variable transmission further comprises a speed ratio shifterconfigured to shift a range of speed ratios to high or lower values. Insome embodiments, the speed ratio shifter comprises a countershaft andgear drivingly engaged with the first ring assembly, the countershaftand gear having a gear ratio that shifts the speed ratio between theinput shaft and the second ring assembly. In some embodiments, the speedratio shifter comprises a planetary gearset, a portion of which isgrounded. In some embodiments, shifting the range of speed ratios tohigher ratios shifts the range of speed ratios between the planetcarrier and sun of the planetary gearset to lower ratios. In someembodiments, the range of speed ratios is such that the range of speedratios between the input shaft and the sun or output spans a negativeratio to a positive ratio. In some embodiments, the range of speedratios is such that the range of speed ratios between the input shaftand the sun or output spans a negative ratio to a positive ratio, thenegative ratio having equal magnitude as the positive ratio. In someembodiments, the variable transmission further comprises a second speedratio shifter configured to shift a range of speed ratios to high orlower values. In some embodiments, the second speed ratio shiftercomprises a planetary gear set comprising a sun, a ring and a gear, oneof which is grounded to create a speed ratio. In some embodiments, twoof the sun, the ring, and the gear, are not grounded and are connectedto the input shaft and the first ring assembly. In some embodiments,shifting the range of speed ratios to higher ratios shifts the range ofspeed ratios between the planet carrier and sun of the planetary gearsetto lower ratios. In some embodiments, the range of speed ratios is suchthat the range of speed ratios between the input shaft and the sun oroutput spans a negative ratio to a positive ratio. In some embodiments,the range of speed ratios is such that the range of speed ratios betweenthe input shaft and the sun or output spans a negative ratio to apositive ratio, the negative ratio having equal magnitude as thepositive ratio. In some embodiments, the variator is an asymmetricvariator. In some embodiments, the asymmetric variator performs thefunction of the speed ratio shifter. In some embodiments, the first ringassembly comprises a first ring assembly engagement portion that isdrivingly engaged with the tiltable variator balls, and second ringassembly comprises a second ring assembly engagement portion that isdrivingly engaged with the tiltable variator balls, and wherein thefirst ring assembly engagement portion is offset from the second ringassembly engagement portion such that the speed ratio is greater than 1or less than 1 when the tiltable variator balls are not tilted. In someembodiments, the variator comprises a traction fluid.

Provided herein are vehicle drivelines comprising: a power source, anyvariable transmission of any configuration described herein or thatwould be obvious to one of skill in the art having read the disclosureherein drivingly engaged with the power source, and a vehicle outputdrivingly engaged with the variable transmission. In some embodiments,the power source is drivingly engaged with the vehicle output. In someembodiments, the vehicle driveline comprises a torsional dampener. Insome embodiments, the vehicle driveline comprises a clutch.

Provided herein are vehicles comprising a variable transmission of anyconfiguration described herein or that would be obvious to one of skillin the art having read the disclosure herein.

Provided herein are methods comprising providing a variable transmissionof any configuration described herein or that would be obvious to one ofskill in the art having read the disclosure herein.

Provided herein are methods comprising providing a vehicle drivelinecomprising a variable transmission of any configuration described hereinor that would be obvious to one of skill in the art having read thedisclosure herein.

Provided herein are methods comprising providing a vehicle comprising avariable transmission of any configuration described herein or thatwould be obvious to one of skill in the art having read the disclosureherein.

INCORPORATION BY REFERENCE

All publications, patents, and patent applications mentioned in thisspecification are herein incorporated by reference to the same extent asif each individual publication, patent, or patent application wasspecifically and individually indicated to be incorporated by reference.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the invention are set forth with particularity inthe appended claims. A better understanding of the features andadvantages of the present invention will be obtained by reference to thefollowing detailed description that sets forth illustrative embodiments,in which the principles of the invention are utilized, and theaccompanying drawings of which:

FIG. 1 is a side sectional view of a ball-type variator;

FIG. 2 is a magnified, side sectional view of a ball of a variator ofFIG. 1 having a symmetric arrangement of a first ring assembly and asecond ring assembly;

FIG. 3 is a block diagram of a continuously variable transmission (CVT)used in an automobile;

FIG. 4A is stick diagram of a power-splitting CVT configuration;

FIG. 4B is stick diagram of an alternate power-splitting CVTconfiguration where the CVP is first;

FIG. 5 is a graph of a speed diagram of the power-splitting CVTconfiguration in FIG. 4;

FIG. 6A is a stick diagram of a power-splitting CVT drivetrain variantwith a gear ratio coupled to the first ring assembly of the variator;

FIG. 6B is a stick diagram of a power-splitting CVT drivetrain variantwith a planetary gear coupled to the first ring assembly of thevariator, instead of a gear ratio;

FIG. 7 is a power split variant configuration speed diagram showing theeffect of coupling the gear ratio to the first ring assembly of thevariator;

FIG. 8 depicts angles in a symmetric embodiment variator;

FIG. 9 depicts angles in an asymmetric embodiment variator;

FIG. 10 shows a stick diagram of a power splitting configuration usingan asymmetric variator;

FIG. 11 is a speed diagram showing the effect of the asymmetric variatoron the system of FIG. 10.

DETAILED DESCRIPTION OF THE INVENTION

Besides these transmissions, Continuously Variable Transmissions or CVTshave been developed. Those CVTs are of many types: belts with variablepulleys, toroidal, and conical, for non-limiting example. The principleof a CVT is that it enables the engine to run at its most efficientrotation speed by changing steplessly the transmission ratio in functionof the speed of the car and the torque demand (throttle position) of thedriver. If needed for example when accelerating, the CVT is configuredto also shift to the most optimum ratio providing more power. A CVT isconfigured to change the ratio from the minimum to the maximum ratiowithout any interruption of the power transmission, as opposed to theopposite of usual transmissions which require an interruption of thepower transmission by disengaging to shift from one discrete ratio toengage the next ratio.

A specific use of CVTs is the Infinite Variable Transmission or IVT.Where the CVT is limited to positive speed ratios, the IVT configurationis configured to perform a neutral gear and even reverse ratiossteplessly. In some embodiments, a CVT is used as an IVT in somedriveline configurations.

Provided herein are configurations of CVTs based on a ball typevariators, also known as CVP, for constant variable planetary. Somegeneral aspects of the CVTs and CVPs are described in US20040616399 orAU2011224083A1, incorporated herein by reference in their entirety. Thetype of CVT provided herein comprises a variator comprising a pluralityof variator balls, depending on the application, two discs or annularrings 995, 996 each having an engagement portion that engages thevariator balls 997, at least. The engagement portions are optionally ina conical or toroidal convex or concave surface contact with thevariator balls, as input (995) and output (996). The variator optionallyincludes an idler 999 contacting the balls as well as shown on FIG. 1.The variator balls are mounted on axles 998, themselves held in a cageor carrier allowing changing the ratio by tilting the variator balls'axes. Other types of ball CVTs also exist like the one produced byMilner, but are slightly different. These alternative ball CVTs areadditionally contemplated herein. The working principle generallyspeaking, of a ball-type variator (i.e. CVP) of a CVT is shown in FIG.2.

The variator itself works with a traction fluid. The lubricant betweenthe ball and the conical rings acts as a solid at high pressure,transferring the power from the first ring assembly (input of thevariator), through the variator balls, to the second ring assembly(output of the variator). By tilting the variator balls' axes, the ratiois changed between input and output. When the axis of each of thevariator balls is horizontal the ratio is one, when the axis is tiltedthe distance between the axis and the contact point change, modifyingthe overall ratio. All the variator balls' axles are tilted at the sametime with a mechanism included in the cage.

In a vehicle, the CVT 330 is used to replace traditional transmissionand is located between the engine (ICE or internal combustion engine)300 and the differential 340 as shown on FIG. 3. A torsional dampener(alternatively called a damper) 310 is optionally introduced between theengine and the CVT to avoid transferring torque peaks and vibrationsthat could damage the CVT. In some configurations this dampener iscoupled with a clutch 320 for the starting function or for allowing theengine to be decoupled from the transmission. In some embodiments, theclutch is located at a different place in the driveline for allowing aninterruption in the transmission of power in the driveline.

Provided herein is a variable transmission comprising: an input shaft; avariator (CVP) comprising a first ring assembly coupled to the inputshaft, a carrier assembly comprising a plurality of tiltable variatorballs drivingly engaged with the first ring assembly, and a second ringassembly drivingly engaged with the tiltable variator balls; and aplanetary gearset comprising a planet carrier drivingly engaged with theinput shaft, a ring drivingly engaged with the second ring assembly ofthe variator, and a sun gear drivingly engaged with the output of thevehicle, and wherein the planetary gearset is configured to split powerof the input shaft between the variator and a mechanical path goingdirectly to the output through the planetary gear set.

In some embodiments, the first ring assembly and the second ringassembly are drivingly coupled over a continuous range of speed ratiosfrom a minimum speed ratio to a maximum speed ratio, and wherein thespeed ratio is controlled by tiltable variator balls. In someembodiments, the variator controls the speed ratio between the two ringassemblies and thus between the planet carrier and ring of the planetarygearset. In some embodiments, a minimum speed ratio and a maximum speedratio between the input shaft and sun of the planetary gearset span arange from negative to positive.

In some embodiments, the variable transmission comprises a dampener (ordamper) coupled to the input shaft and disposed between a power sourceand the variable transmission.

In some embodiments, the variable transmission comprises a speed ratioshifter configured to shift a range of speed ratios to high or lowervalues. In some embodiments, the speed ratio shifter comprises acountershaft and gear drivingly engaged with the first ring assembly,the countershaft and gear having a gear ratio that changes the speedratio between the input shaft and the second ring assembly. In someembodiments, shifting the range of speed ratios to higher ratios shiftsthe range of speed ratios between the planet carrier and sun of theplanetary gearset to lower ratios. In some embodiments, the range ofspeed ratios is such that the range of ICE speed ratios spans a negativeratio to a positive ratio. The speed ratio shifter or the second speedratio shifter may comprise a planetary gear set.

In some embodiments, the variator is an asymmetric variator. In someembodiments, the asymmetric variator perform as a speed ratio shifter.In some embodiments, the first ring assembly comprises a first ringassembly engagement portion that is drivingly engaged with the variatorball, and second ring assembly comprises a second ring assemblyengagement portion that is drivingly engaged with the variator ball, andwherein the first ring assembly engagement portion is offset from thesecond ring assembly engagement portion such that the speed ratio isgreater than 1 or less than 1 when the variator balls are not tilted.

In some embodiments, the variator comprises a traction fluid.

Provided herein is a vehicle driveline comprising: a power source, avariable transmission of any configuration described herein or thatwould be obvious to one of skill in the art having read the disclosureherein. In some embodiments, the variable transmission of the vehicledriveline is drivingly engaged with the power source, and a vehicleoutput drivingly engaged with the variable transmission.

In some embodiments, the power source is drivingly engaged with thevehicle output. In some embodiments, the vehicle driveline comprises atorsional dampener. In some embodiments, the vehicle driveline comprisesa clutch. In some embodiments, the vehicle driveline comprises avariable transmission of any configuration described herein or thatwould be obvious to one of skill in the art having read the disclosureherein.

Provided herein is a method comprising providing a variable transmissionof any configuration described herein or that would be obvious to one ofskill in the art having read the disclosure herein.

Provided herein is a method comprising providing a vehicle drivelinecomprising a variable transmission of any configuration described hereinor that would be obvious to one of skill in the art having read thedisclosure herein.

Provided herein is a method comprising providing a vehicle comprising avariable transmission of any configuration described herein or thatwould be obvious to one of skill in the art having read the disclosureherein.

Provided herein are variable transmissions comprising: an input shaft; avariator (CVP) comprising a first ring assembly coupled to the inputshaft, a carrier assembly comprising a plurality of tiltable variatorballs drivingly engaged with the first ring assembly, and a second ringassembly drivingly engaged with the tiltable variator balls; and aplanetary gearset comprising a planet carrier drivingly engaged with theinput shaft, a ring drivingly engaged with the second ring assembly ofthe variator, and a sun gear drivingly engaged with the output of thevehicle, wherein the planetary gearset is configured to split power ofthe input shaft between the variator and a mechanical path goingdirectly to the output through the planetary gear set. In someembodiments, the first ring assembly and the second ring assembly aredrivingly coupled over a continuous range of speed ratios from a minimumspeed ratio to a maximum speed ratio, and wherein the speed ratio iscontrolled by the tiltable variator balls. In some embodiments, thetiltable variator balls controls the speed ratio between the first ringassembly and second ring assembly of the variator, and thereby controlsthe speed ratio between the planet carrier and ring of the planetarygearset. In some embodiments, a minimum speed ratio and a maximum speedratio between the input shaft and the sun of the planetary gearset spana range from negative to positive. In some embodiments, the variabletransmission further comprises a damper coupled to the input shaft anddisposed between a power source and the variable transmission. In someembodiments, the variable transmission further comprises a clutchdisposed between the power source and the variable transmission. In someembodiments, the clutch is coupled to the damper or at a location toallow interrupting power transmission. In some embodiments, the variabletransmission further comprises a speed ratio shifter configured to shifta range of speed ratios to high or lower values. In some embodiments,the speed ratio shifter comprises a countershaft and gear drivinglyengaged with the first ring assembly, the countershaft and gear having agear ratio that shifts the speed ratio between the input shaft and thesecond ring assembly. In some embodiments, the speed ratio shiftercomprises a planetary gearset, a portion of which is grounded. In someembodiments, shifting the range of speed ratios to higher ratios shiftsthe range of speed ratios between the planet carrier and sun of theplanetary gearset to lower ratios. In some embodiments, the range ofspeed ratios is such that the range of speed ratios between the inputshaft and the sun or output spans a negative ratio to a positive ratio.In some embodiments, the range of speed ratios is such that the range ofspeed ratios between the input shaft and the sun or output spans anegative ratio to a positive ratio, the negative ratio having equalmagnitude as the positive ratio. In some embodiments, the variabletransmission further comprises a second speed ratio shifter configuredto shift a range of speed ratios to high or lower values. In someembodiments, the second speed ratio shifter comprises a planetary gearset comprising a sun, a ring and a gear, one of which is grounded tocreate a speed ratio. In some embodiments, two of the sun, the ring, andthe gear, are not grounded and are connected to the input shaft and thefirst ring assembly. In some embodiments, shifting the range of speedratios to higher ratios shifts the range of speed ratios between theplanet carrier and sun of the planetary gearset to lower ratios. In someembodiments, the range of speed ratios is such that the range of speedratios between the input shaft and the sun or output spans a negativeratio to a positive ratio. In some embodiments, the range of speedratios is such that the range of speed ratios between the input shaftand the sun or output spans a negative ratio to a positive ratio, thenegative ratio having equal magnitude as the positive ratio. In someembodiments, the variator is an asymmetric variator. In someembodiments, the asymmetric variator performs the function of the speedratio shifter. In some embodiments, the first ring assembly comprises afirst ring assembly engagement portion that is drivingly engaged withthe tiltable variator balls, and second ring assembly comprises a secondring assembly engagement portion that is drivingly engaged with thetiltable variator balls, and wherein the first ring assembly engagementportion is offset from the second ring assembly engagement portion suchthat the speed ratio is greater than 1 or less than 1 when the tiltablevariator balls are not tilted. In some embodiments, the variatorcomprises a traction fluid.

Provided herein are vehicle drivelines comprising: a power source, anyvariable transmission of any configuration described herein or thatwould be obvious to one of skill in the art having read the disclosureherein drivingly engaged with the power source, and a vehicle outputdrivingly engaged with the variable transmission. In some embodiments,the power source is drivingly engaged with the vehicle output. In someembodiments, the vehicle driveline comprises a torsional dampener. Insome embodiments, the vehicle driveline comprises a clutch.

Provided herein are vehicles comprising a variable transmission of anyconfiguration described herein or that would be obvious to one of skillin the art having read the disclosure herein.

Provided herein are methods comprising providing a variable transmissionof any configuration described herein or that would be obvious to one ofskill in the art having read the disclosure herein.

Provided herein are methods comprising providing a vehicle drivelinecomprising a variable transmission of any configuration described hereinor that would be obvious to one of skill in the art having read thedisclosure herein.

Provided herein are methods comprising providing a vehicle comprising avariable transmission of any configuration described herein or thatwould be obvious to one of skill in the art having read the disclosureherein.

Example 1

Some embodiments of the invention are directed to variable transmissionconfigurations that includes a variator (alternatively called a CVPherein) and a planetary gearset that together are able to providestandstill and reverse functions (such as is possible in a typicalIVT—infinitely variable transmission). As such, no starting device (likea slipping clutch or a torque converter) is required. Rather, thevariable transmission configuration described herein, and shown in anembodiment configuration in FIG. 4, provides the starting function forthe vehicle driveline powered by, for example, an engine.

Thus, certain embodiments of a variable transmission comprise a variatorcoupled to a planetary gear system. For example, in some embodiments,the planetary gearset is an epicyclic gearset. The planetary gearsetcomprises the carrier a plurality of planet gears, a sun gear, and aring gear. The carrier, the sun gear, and the ring gear are rotatablydisposed in the transmission housing. Each of the planet gears isrotatably disposed on the carrier and is drivingly engaged with the sungear and the ring gear. The sun gear is drivingly engaged with theoutput of the transmission. The ring gear is drivingly engaged with thesecond variator ring assembly; however, it is understood that the ringgear is optionally integrally formed with the second ring assembly.

As shown in FIG. 4A, an internal combustion engine (ICE) or any otherpower plant is coupled to a power-splitting CVT configuration 400comprising a variator 460 at the first ring assembly (input ring) 461 ofthe variator and the planet carrier 430 of the planetary gearset 450.The output ring of the variator (second ring assembly) 462 is coupled tothe ring 410 of the planetary gearset and the sun gear 420 of theplanetary gearset is the output of the transmission and is coupled tothe differential 470 and drive axle of the vehicle. The ICE is linkeddirectly to the planet gears 440 through the carrier but also indirectlythrough ring via the variator. However the connection to the ring issubject to the speed ratio of the variator. Through the variatorcontrols the flow of power from the ICE through the planetary gearset.As shown in FIG. 5, by varying the variator speed ratio between themaximum and minimum capabilities for the variator the speed ratiobetween the ICE input and output is configured to change drasticallyover a continuum that includes both positive and negative values. Thisgives the ICE the ability to seamlessly achieve forward, neutral, andreverse gearing.

As shown in FIG. 4A, an internal combustion engine (ICE) or any otherpower plant is coupled to a power-splitting CVT configuration 400comprising a variator 460 at the first ring assembly (input ring) 461 ofthe variator and the planet carrier 430 of the planetary gearset 450.The output ring of the variator (second ring assembly) 462 is coupled tothe ring 410 of the planetary gearset and the sun gear 420 of theplanetary gearset is the output of the transmission and is coupled tothe differential 470 and drive axle of the vehicle. The ICE is linkeddirectly to the planet gears 440 through the carrier but also indirectlythrough ring via the variator. However the connection to the ring issubject to the speed ratio of the variator. Through the variatorcontrols the flow of power from the ICE through the planetary gearset.As shown in FIG. 5, by varying the variator speed ratio between themaximum and minimum capabilities for the variator the speed ratiobetween the ICE input and output is configured to change drasticallyover a continuum that includes both positive and negative values. Thisgives the ICE the ability to seamlessly achieve forward, neutral, andreverse gearing.

Alternately, as shown in FIG. 4B, an internal combustion engine (ICE) orany other power plant is coupled to a power-splitting CVT configuration405 just as shown in FIG. 4A, with the exception that the CVP is placedfirst in this arrangement, and also comprises a variator 460 at thefirst ring assembly (input ring) 461 of the variator and the planetcarrier 430 of the planetary gearset 450. The output of the variator 462is coupled to the ring 410 of the planetary gearset and the sun gear 420of the planetary gearset is the output of the transmission and iscoupled to the differential 470 and drive axle of the vehicle. The ICEis linked directly to the planet gears 440 through the carrier but alsoindirectly through ring via the variator. However the connection to thering is subject to the speed ratio of the variator. Through the variatorcontrols the flow of power from the ICE through the planetary gearset.This variation also gives the ICE the ability to seamlessly achieveforward, neutral, and reverse gearing.

The three horizontal axes of FIG. 5 represent respectively, from thebottom to the top, the sun rotation speed 510, the planet carrierrotation speed 511 and the ring rotation speed 512. The planet carrier430 is linked to the ICE and then always turns at the ICE speed, shownas a vertical bar 513 at the intersection of the crossing dotted lines514, 515 on the carrier axis. The ring 410 is connected to the secondring assembly (output) 462 of the variator and is thus turning at aspeed included between the ICE speed times the minimum ratio of the CVP(variator) and the ICE speed times the maximum speed ratio of the CVP(variator). This speed interval 516 is shown on the top horizontal axisbeginning to the right of zero beneath ICE*CVP min ratio label extendingto the right beneath the ICE*CVP max ratio label on the ring axis.

The highlighted interval 517 along the lower horizontal axisrepresenting the Sun's Rotation speed, which extends from just above theMax REV Speed to the Max FWD speed in FIG. 5 shows the speed achievableby the sun depending on the variator speed ratio. A minimum speed ratioin the variator brings the sun speed to its maximum while the maximumspeed ratio in the CVP brings the sun speed to its maximum negativespeed. The area comprised in between the dotted lines 514, 515 can becompletely covered by only changing the speed ratio in the CVP. It canbe observed that the amount of positive speeds achievable with thatconfiguration is bigger than the negatives ones.

This configuration is a power split configuration, meaning that thereare multiple power paths that will be used at the same time. A part ofthe power will flow through the CVP (variator), the planetary ring,planet and going out through the sun while a certain amount of the powerwill directly flow through the carrier, planets and sun of theplanetary.

Example 2

A variant of the previous example comprises a gear ratio at the firstring assembly (input) of the variator, for example, as shown in FIG. 6A.As with Example 1, this configuration 600 uses a planetary gearset 650to provide different power paths and a gear ratio 680 before the firstring assembly 661 of the variator 660. Thanks to the planetary gearset,the configuration uses only a variator yet is able to provide standstilland reverse function as an infinitely variable transmission would. Nostarting device like a slipping clutch or torque converter is required,since the infinitely variable transmission of the embodiment CVTdescribed in this example, at least, takes care of the startingfunction. The added gear ratio gives the ability to increase thecoverage of reverse speeds and also decreases the torque on thevariator.

Adding a gear ratio 680 greater than 1 to the input of the variator (theinput to the variator depicted on the left of the variator 660 in FIG.6A) shifts the planetary gear set 650 min speed and planetary gear setmax speed higher levels. Indeed, the speed ratios are the same, butmultiplied by a value greater than one. This has the effect of changingthe output speed range (as reflected by the planetary sun near'srotation) to lower levels. The effect is magnified by the planetarycarrier/sun gear ratio allowing much more negative speed than before.Some embodiments of the invention feature a gear ratio mechanicallyplaced on the other side of the CVP (but still linked to the first ringassembly or input of the variator) for the purpose of changing theoverall speed/gear ratio range of the transmission.

Thus, the embodiment 600 of FIG. 6A includes an ICE drivingly engagedwith a planet carrier 630 of a planetary gearset 650. The ICE is linkeddirectly to the planet gears 640 through the carrier but also indirectlythrough the ring gear 610 via the variator 660. A gear ratio 680comprises a gear 681 on the input shaft, a counter shaft 670 and a gear682 on the input ring (first ring assembly) 661 of the variator 660.Note that this gear ratio is optionally obtained with another layoutsuch as a planetary of which one of the elements is fixed. This geararrangement is presented to provide a first speed ratio between the ICEand the first ring assembly without changing the rotation directionbetween the ICE and the first ring assembly. The variator second ringassembly 662 is then connected to the ring 610 of the planetary gearset650. The sun 620 of the planetary gearset is directly connected to anoutput of the transmission 690, which itself is linked to thedifferential and the wheel axle in a vehicle driveline embodiment.

Yet another variant of the previous example comprises a planetary gearat the first ring assembly (input) of the variator, for example, asshown in FIG. 6B. As with Example 1, this configuration 605 uses a firstplanetary gearset 650 to provide different power paths and a secondplanetary gear set 655 before the first ring assembly 661 of thevariator 660. Thanks to the first planetary gearset, the configurationuses only a variator, yet is able to provide standstill and reversefunction as an infinitely variable transmission would. No startingdevice like a slipping clutch or torque converter is required, since theinfinitely variable transmission of the embodiment CVT described in thisexample, at least, takes care of the starting function. The added secondplanetary gear set gives the ability to increase the coverage of reversespeeds and also decreases the torque on the variator.

As suggested previously, adding a second planetary gear set 655 whichperforms the same up-speed function of the gear ratio described in FIG.6A, wherein the sun gear 625 is locked to ground, and having a greaterthan 1 ratio to the input of the variator (the input to the variatordepicted on the left of the variator 660 in FIG. 6B) shifts the secondplanetary gear set 650 min speed and planetary gear set max speed tohigher levels. Again, the speed ratios are the same, but multiplied by avalue greater than one. This also has the effect of changing the outputspeed range (as reflected by the second planetary sun gear's rotation)to lower levels. The effect is magnified by the planetary carrier/sungear ratio allowing much more negative speed than before. Someembodiments of the invention feature a first planetary gear setmechanically placed on the other side of the CVP (but still linked tothe first ring assembly or input of the variator) for the purpose ofchanging the overall speed/gear ratio range of the transmission.

Thus, the embodiment 605 of FIG. 6B includes an ICE drivingly engagedwith a first planet carrier 630 of a first planetary gearset 650. TheICE is linked directly to the first planet gears 640 through the carrierbut also indirectly through the first ring gear 610 via the variator660. A second planetary gearset 655 comprises a second carrier 635 onthe input shaft, linking the ICE directly to the second planet gears645, where the second sun gear 625 is locked to ground, and the secondplanets drivingly engage the second ring gear 615 which is linked to theinput ring (first ring assembly) 661 of the variator 660. This secondplanetary gear arrangement is presented to provide a first speed ratiobetween the ICE and the first ring assembly 661 without changing therotation direction between the ICE and the first ring assembly. Thevariator second ring assembly 662 is then connected to the first ring610 of the first planetary gearset 650. The first sun 620 of the firstplanetary gearset 650 is directly connected to an output of thetransmission 690, which itself is linked to the differential and thewheel axle in a vehicle driveline embodiment.

FIG. 7 depicts a speed diagram of the power split embodiment depicted inFIG. 6.

The three horizontal axes represent respectively, from the bottom to thetop, the sun rotation speed 701, the planet carrier rotation speed 702and the ring rotation speed 703. The planet carrier 630 is linked to theICE and then always turns at the ICE speed, shown as a small dottedlines 704 crossing on the carrier axis. The ring 610 is connected to thesecond ring assembly (output) 662 of the variator (CVP) 660 and is thusturning at a speed included in the following interval [ICE*CVP minRatio*Gear speed ratio; ICE*CVP max Ratio*Gear speed ratio]. This speedinterval 705 is shown on the top horizontal axis starting just to theright of the first vertical bar crossing the axis, under the ICE*CVP minratio*gear ratio label, and extending to the right past the third, 3rd,vertical bar crossing the ring axis ending above the “R” of the Rotationspeed label on the ring axis. For reference, the dotted line 706 shownjust below the ring axis shows the interval without gear ratio as it wasin the previous example (Example 1).

The solid line 707 along the lower horizontal axis, representing theSun's Rotation speed, which extends from just above the Max REV Speedlabel to the Max FWD speed label on the sun axis shows the speedachievable by the sun depending on the variator speed ratio. A minimumspeed ratio in the variator brings the sun speed to its maximum whilethe maximum speed ratio in the CVP brings the sun speed to its maximumnegative speed. The area comprised in between the small dotted lines708, 709 can be completely covered by only changing the speed ratio inthe CVP. Thanks to this design, the amount of negative speeds can beincreased compared to the previous configuration. Such a feature isimportant in some applications such as Off-Highway applications in whichthe requirements include the same magnitude of positive and negativespeeds. For reference, the other dotted line 710, shown just above thesun axis shows the interval without gear ratio as it was in the previousexample (Example 1).

The ratio at the input of the CVP is optionally configured or setaccording to the specifications of the vehicle. It has to be understoodthat this ratio is optionally bigger than 1 or smaller than 1. A speedratio bigger than one increases the speed of the variator input ringwhile a gear speed ratio smaller than one decreases the speed of thevariator input ring. Similarly, the counter shaft is optionally omittedif the objective is to reverse the speed of the variator input ring.

The embodiments of Example 1 and 2 are power split configurations,meaning that there are multiple power paths that will be used at thesame time. A part of the power will flow through the variator, theplanetary ring, planet and going out through the sun, while a certainamount of the power will directly flow through the carrier, planets andsun of the planetary gearset. Such configurations of power splittingvariable transmissions (CVTs) allow, for instance, an ICE with thecapability to go just as fast in forward gearing as in reverse. In someembodiments, coupling a gear ratio to the variator (CVP) is accomplishedwith gears and countershafts. However it is desirable to not complicatethe hardware of the transmission more than necessary.

Example 3

An internal speed ratio is alternatively created using an asymmetricvariator rather than the power split configurations of Example 1 andExample 2. Such a configuration eliminates need for the ratio gears andcountershaft or planetary gear set of Example 2, thus reducing the partsof the overall variable transmission while providing the samefunctionality. Additionally, an asymmetric variator that changes alphaangles (described elsewhere herein) could be used in many other cases,increasing the spread, or giving better efficiency for a certain rangeof speed ratios

Thus, some embodiments of a variable transmission that includes abiasing gear ratio on the variator. This is optionally achieved bymodifying the variator to produce an asymmetric variator design. FIG. 8shows a standard ball variator 800 used in the variable transmission.The first ring assembly 801 (input ring) and second ring assembly 802(output ring) are mechanically coupled to each variator ball 803 at twopoints. The first ring assembly turns at a speed Omega 1 around thehorizontal while the second ring assembly turns at a speed Omega 2around the horizontal. The angle between the ball axle and thehorizontal is called Gamma and the angle between the normal to thecontact patch of the first ring assembly and the vertical is calledAlpha 1 while the angle between the normal to the contact patch of thesecond ring assembly and the vertical is called Alpha 2. In somevariators, Alpha 1 is the same as Alpha 2 and the speed ratio given by

${SR} = {\frac{{Omega}_{2}}{{Omega}_{1}} = {\frac{\cos \left( {{Alpha}_{2} - {Gamma}} \right)}{\cos \left( {{Alpha}_{1} + {Gamma}} \right)} = 1}}$

when the ball is not tilted (gamma=0).

Provided herein is an alternative variator 900, and variabletransmission employing such a variator, which uses different anglesAlpha 1 and Alpha 2, as shown on FIG. 9. In such an arrangement, thespeed ratio is no longer 1 when gamma=0. Such an embodiment is anasymmetric variator (asymmetric CVP). The geometry of the variator nowfavors a SR (speed ratio) greater or less than 1. In effect, its rangeof attainable speed ratio shift being dependent upon which isgreater—Alpha 1 or Alpha 2. If Alpha 1 is greater than Alpha 2 then thespeed ratio range shifts to faster values and vice versa. In someembodiments, an asymmetric variator (asymmetric CVP) is used to alterthe overall gearing range of the ICE without the use of extra gearing.FIG. 10 and FIG. 11 depict a power splitting driveline configurationwith an asymmetric variator. Modifying the variator speed ratio rangehas the same effect as seen in FIG. 7, of broadening and lowering theoutput rotation speed range.

The embodiment 1000 of FIG. 10 comprises a planetary gearset 1050 toprovide different power paths. The central part of the configuration ofFIG. 10 is the variator 1060 described previously in the document withan asymmetric design 900 of the first ring assembly 901 (variator inputring) and second ring assembly 902 (variator output ring).

As shown in FIG. 10, an internal combustion engine (ICE) or any otherpower plant is coupled to a power-splitting CVT configuration 1000comprising an asymmetric variator 1060 at the first ring assembly (inputring) 901 of the variator and the planet carrier 1030 of the planetarygearset 1050. The output of the asymmetric variator 902 is coupled tothe ring 1010 of the planetary gearset and the sun gear 1020 of theplanetary gearset is the output of the transmission and is coupled tothe differential 1070 and drive axle of the vehicle. The ICE is linkeddirectly to the planet gears 1040 through the carrier but alsoindirectly through ring 1010 via the asymmetric variator 1060. Howeverthe connection to the ring is subject to the speed ratio of thevariator. Through the variator controls the flow of power from the ICEthrough the planetary gearset.

A ball ramp on each side of the variator provides the clamping forcenecessary to transfer the torque. Due to the planetary gearset, theconfiguration of FIG. 10 uses only a variator (no gear ratio elements)and is able to provide standstill and reverse function as an IVP. Nostarting device like a slipping clutch or torque converter is required,since the IVP capability takes care of the starting function. FIG. 11shows the speed diagram of the embodiment of FIG. 10, which is similarto the speed diagram in FIG. 9.

The three horizontal axes of FIG. 11 represent respectively, from thebottom to the top, the sun rotation speed 1101, the planet carrierrotation speed 1102 and the ring rotation speed 1103. The planet carrier1030 is linked to the ICE and then always turns at the ICE speed, shownas a vertical bar 1104 where the small dotted lines 1105, 1106 intersecton the carrier axis. The ring is connected to the output 902 (secondring assembly) of the CVP 1060 and is thus turning at a speed includedin the following interval [ICE*CVP min Ratio; ICE*CVP max Ratio]. Thisspeed interval 1107 is shown on the top horizontal axis starting just tothe right of the first vertical bar crossing the axis, under the ICE*CVPmin ratio*gear ratio label, and extending to the right pat the third,3rd, vertical line crossing the ring axis ending above the “R” of theRotation speed label on the ring axis. For reference, the other dottedline 1108 shown just above the sun axis shows the interval for asymmetric CVP as it was in Example 1 (FIG. 7).

The solid interval 1109 on the sun axis shows the speed achievable onthe sun depending on the variator speed ratio. A minimum speed ratio inthe variator brings the sun speed to its maximum while the maximum speedratio in the variator brings the sun speed to its maximum negativespeed. The area comprised in between the dotted lines 1105, 1106 can becompletely covered by only changing the speed ratio in the CVP. Thanksto this design, the amount of negative speeds can be increased comparedto the previous configuration of Example 1. Such a feature is importantin some applications such as Off-Highway applications in which therequirements include the same magnitude of positive and negative speeds.For reference, the dotted line 1110 on the ring axis shows the intervalwithout gear ratio as it was in Example 1.

This configuration is a power split configuration, meaning that thereare multiple power paths that will be used at the same time. A part ofthe power will flow through the variator, the planetary ring, planet andgoing out through the sun while a certain amount of the power willdirectly flow through the planet carrier, planets and sun of theplanetary gearset.

The ICE in the embodiment of FIG. 10 is connected to the planet carrier1030 of the planetary 1050 and to the input ring 901 (first ringassembly) of the CVP 1060. Additionally, the ICE is linked directly tothe planet gears 1040 through the carrier but also indirectly throughring 1010 via the asymmetric variator 1060. The variator output ring 902(second ring assembly) is then connected to the ring 1010 of theplanetary 1050. The sun 1020 of the planetary is directly connected tothe output 1070 of the transmission, itself linked to the differentialand the wheel axle.

Embodiments of the variable transmission described herein or that wouldbe obvious to one of skill in the art upon reading the disclosureherein, are contemplated for use in a variety of vehicle drivelines. Fornon-limiting example, the variable transmissions disclosed herein isused in bicycles, mopeds, scooters, motorcycles, automobiles, electricautomobiles, trucks, sport utility vehicles (SUV's), lawn mowers,tractors, harvesters, agricultural machinery, all terrain vehicles(ATV's), jet ski's, personal watercraft vehicles, airplanes, trains,helicopters, buses, forklifts, golf carts, motorships, steam poweredships, submarines, space craft, or other vehicles that employ atransmission.

While the figures and description herein are directed to ball-typevariators (CVTs), alternate embodiments are contemplated another versionof a variator (CVT), such as a Variable-diameter pulley (VDP) or Reevesdrive, a toroidal or roller-based CVT (Extroid CVT), a Magnetic CVT ormCVT, Ratcheting CVT, Hydrostatic CVTs, Naudic Incremental CVT (iCVT),Cone CVTs, Radial roller CVT, Planetary CVT, or any other version CVT.

While preferred embodiments of the present invention have been shown anddescribed herein, it will be obvious to those skilled in the art thatsuch embodiments are provided by way of example only. Numerousvariations, changes, and substitutions will now occur to those skilledin the art without departing from the invention. It should be understoodthat various alternatives to the embodiments of the invention describedherein are optionally employed in practicing the invention. It isintended that the following claims define the scope of the invention andthat methods and structures within the scope of these claims and theirequivalents be covered thereby.

What is claimed is:
 1. A variable transmission comprising: an input shaft; a variator (CVP) comprising a first ring assembly drivingly engaged to the input shaft, a carrier assembly comprising a plurality of tiltable variator balls drivingly engaged with the first ring assembly, and a second ring assembly drivingly engaged with the tiltable variator balls; and a planetary gearset comprising a planet carrier coupled with the input shaft, a ring gear drivingly engaged with the second ring assembly of the variator, and a sun gear drivingly engaged with an output of a vehicle, wherein the variator is placed first in a transmission arrangement, wherein the variator controls the flow of power from a power source through the ring gear of the planetary gearset and is subject to the speed ratio of the variator, wherein the planetary gearset is configured to split power of the input shaft between the variator and a mechanical path going directly to the output through the planetary gear set.
 2. The variable transmission of claim 1, wherein the first ring assembly and the second ring assembly are drivingly coupled over a continuous range of speed ratios from a minimum speed ratio to a maximum speed ratio, and wherein the speed ratio is controlled by the tiltable variator balls.
 3. The variable transmission of claim 1, wherein the tiltable variator balls controls the speed ratio between the first ring assembly and second ring assembly of the variator, and thereby controls the speed ratio between the planet carrier and ring of the planetary gearset.
 4. The variable transmission of claim 1, wherein a minimum speed ratio and a maximum speed ratio between the input shaft and the sun of the planetary gearset span a range from negative to positive.
 5. The variable transmission of claim 1, further comprising a damper coupled to the input shaft and disposed between a power source and the variable transmission.
 6. The variable transmission of claim 5, further comprising a clutch disposed between the power source and the variable transmission.
 7. The variable transmission of claim 6, wherein the clutch is coupled to the damper or at a location to allow interrupting power transmission.
 8. The variable transmission of claim 1, further comprising a speed ratio shifter configured to shift a range of speed ratios to high or lower values.
 9. The variable transmission of claim 8, wherein the speed ratio shifter comprises a countershaft and gear drivingly engaged with the first ring assembly, the countershaft and gear having a gear ratio that shifts the speed ratio between the input shaft and the second ring assembly.
 10. The variable transmission of claim 8, wherein the speed ratio shifter comprises a planetary gearset, a portion of which is grounded.
 11. The variable transmission of claim 8, wherein shifting the range of speed ratios to higher ratios shifts the range of speed ratios between the planet carrier and sun of the planetary gearset to lower ratios.
 12. The variable transmission of claim 8, wherein the range of speed ratios is such that the range of speed ratios between the input shaft and the sun or output spans a negative ratio to a positive ratio.
 13. The variable transmission of claim 12, wherein the range of speed ratios is such that the range of speed ratios between the input shaft and the sun or output spans a negative ratio to a positive ratio, the negative ratio having equal magnitude as the positive ratio.
 14. The variable transmission of claim 8, further comprising a second speed ratio shifter configured to shift a range of speed ratios to high or lower values.
 15. The variable transmission of claim 14, wherein the second speed ratio shifter comprises a planetary gear set comprising a sun, a ring and a gear, one of which is grounded to create a speed ratio.
 16. The variable transmission of claim 15, wherein two of the sun, the ring, and the gear, are not grounded and are connected to the input shaft and the first ring assembly.
 17. The variable transmission of claim 14, wherein shifting the range of speed ratios to higher ratios shifts the range of speed ratios between the planet carrier and sun of the planetary gearset to lower ratios.
 18. The variable transmission of claim 14, wherein the range of speed ratios is such that the range of speed ratios between the input shaft and the sun or output spans a negative ratio to a positive ratio.
 19. The variable transmission of claim 14, wherein the range of speed ratios is such that the range of speed ratios between the input shaft and the sun or output spans a negative ratio to a positive ratio, the negative ratio having equal magnitude as the positive ratio.
 20. The variable transmission of claim 8, wherein the variator is an asymmetric variator.
 21. The variable transmission of claim 20, wherein the asymmetric variator performs the function of the speed ratio shifter.
 22. The variable transmission of claim 20, wherein the first ring assembly comprises a first ring assembly engagement portion that is drivingly engaged with the tiltable variator balls, and second ring assembly comprises a second ring assembly engagement portion that is drivingly engaged with the tiltable variator balls, and wherein the first ring assembly engagement portion is offset from the second ring assembly engagement portion such that the speed ratio is greater than 1 or less than 1 when the tiltable variator balls are not tilted.
 23. The variable transmission of claim 1, wherein the variator comprises a traction fluid. 24.-31. (canceled)
 32. A variable transmission comprising: an input shaft; a variator comprising a first ring assembly, a carrier assembly comprising a plurality of tiltable variator balls drivingly engaged with the first ring assembly, and a second ring assembly drivingly engaged with the tiltable variator balls; and a first planetary gearset comprising a planet carrier drivingly engaged with the input shaft, a ring gear drivingly engaged with the second ring assembly of the variator, and a sun gear drivingly engaged with an output of a vehicle, a second planetary gearset comprising a planet carrier drivingly engaged with the input shaft, a ring gear drivingly engaged with the first ring assembly of the variator and a sun gear locked to ground wherein the second planetary gearset comprises a greater than one ratio to the first ring assembly of the variator, wherein the first planetary gearset is configured to split power of the input shaft between the variator and a mechanical path going directly to the output through the first planetary gear set.
 33. The variable transmission of claim 32, wherein the variator is placed first in a transmission arrangement. 